Also known as: reasonable-certainty standard · reasonable certainty · reasonable certainty requirement · certainty standard
Written by attorneys · grounded in primary & secondary sources — see below
A requirement that facts essential to a claim or defense be shown by evidence that permits a reasonable determination of their existence or amount without speculation.
Rosa Ruiz and Ridgeway Partners exchanged emails about selling a warehouse. The signed messages identified the property and price but omitted the closing date and financing terms. When Ridgeway later refused to perform, Rosa sued for breach. The court held the writings failed the reasonable certainty standard because the essential unperformed promises remained too vague to enforce.
Riley Rivera executed a will that referred to a separate inventory of jewelry. The inventory existed at execution and the will clearly expressed intent to incorporate it. When probate began, the inventory described each item and beneficiary with enough detail for identification. The court allowed incorporation because the writing met the reasonable certainty standard.
Select any source to read its text and confirm it supports the definition.
Police obtained a warrant for an unidentified man who robbed a store. The complaint described the suspect as a six-foot-tall male with a distinctive scar on his left cheek and a red baseball cap. Officers later arrested Ricardo Rojas, who matched the description exactly. The court upheld the warrant because the description identified the defendant with reasonable certainty.
Rina Rahman bought a franchise from Riverside Healthcare after the seller misrepresented its patient volume. She proved the actual volume was far lower and calculated the resulting shortfall in revenue. Expert testimony tied the shortfall directly to the misrepresentations and supplied concrete figures. The court awarded the additional damages because they were proved with reasonable certainty.
Robert Rivera spent $180,000 preparing a site for a warehouse under an oral agreement with Riverfront Developments. When Riverfront repudiated, Robert sought recovery of his outlays. He documented every expenditure with invoices and canceled checks. The court permitted reliance damages because the amounts were shown with reasonable certainty and Riverfront could not prove any loss Robert would have suffered anyway.
Roland Rhodes contracted to supply custom software to Rhapsody Entertainment. After breach, Roland claimed $2 million in lost profits from future licensing deals. His projections rested on hoped-for contracts with no signed commitments or historical sales data. The court denied the claim because the evidence did not establish the lost profits with reasonable certainty.
The plaintiff must supply evidence that permits a reasonable determination of the amount without speculation. Courts traditionally demand greater certainty for contract damages than for tort damages. Projections based solely on hoped-for future deals usually fail, while figures grounded in the plaintiff's own track record or comparable transactions can satisfy the standard.
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Reliance expenditures actually made are usually easy to prove with reasonable certainty through invoices and records. The breaching party may still reduce the award by showing with reasonable certainty that the injured party would have suffered a net loss even if the contract had been performed.
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Yes. The writing must state the essential terms of the unperformed promises with reasonable certainty. Omission of key terms such as closing dates, payment schedules, or scope of coverage renders the memorandum insufficient even if the subject matter is identified.
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…mitigates the degree of criminality or punishment, we think the State may assure itself that the fact has been established with reasonable certainty. To recognize at all a mitigating circumstance does not require the State to prove its nonexistence in each case in which the fact is put in issue, if in its judgment this would be too…